From fd837b08d98c0c9f4f31998f2ed55b9d8694082c Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Mon, 8 Aug 2016 17:29:28 +0100 Subject: KVM: arm64: ITS: return 1 on successful MSI injection According to the KVM API documentation a successful MSI injection should return a value > 0 on success. Return possible errors in vgic_its_trigger_msi() and report a successful injection back to userland, while also reporting the case where the MSI could not be delivered due to the guest not having the LPI mapped, for instance. Signed-off-by: Andre Przywara Reviewed-by: Eric Auger Reviewed-by: Christoffer Dall Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic/vgic-its.c | 56 +++++++++++++++++++++++++++++--------------- 1 file changed, 37 insertions(+), 19 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 07411cf967b9..1bd8adbeae26 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -441,39 +441,48 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm, * Find the target VCPU and the LPI number for a given devid/eventid pair * and make this IRQ pending, possibly injecting it. * Must be called with the its_lock mutex held. + * Returns 0 on success, a positive error value for any ITS mapping + * related errors and negative error values for generic errors. */ -static void vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, - u32 devid, u32 eventid) +static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, + u32 devid, u32 eventid) { + struct kvm_vcpu *vcpu; struct its_itte *itte; if (!its->enabled) - return; + return -EBUSY; itte = find_itte(its, devid, eventid); - /* Triggering an unmapped IRQ gets silently dropped. */ - if (itte && its_is_collection_mapped(itte->collection)) { - struct kvm_vcpu *vcpu; - - vcpu = kvm_get_vcpu(kvm, itte->collection->target_addr); - if (vcpu && vcpu->arch.vgic_cpu.lpis_enabled) { - spin_lock(&itte->irq->irq_lock); - itte->irq->pending = true; - vgic_queue_irq_unlock(kvm, itte->irq); - } - } + if (!itte || !its_is_collection_mapped(itte->collection)) + return E_ITS_INT_UNMAPPED_INTERRUPT; + + vcpu = kvm_get_vcpu(kvm, itte->collection->target_addr); + if (!vcpu) + return E_ITS_INT_UNMAPPED_INTERRUPT; + + if (!vcpu->arch.vgic_cpu.lpis_enabled) + return -EBUSY; + + spin_lock(&itte->irq->irq_lock); + itte->irq->pending = true; + vgic_queue_irq_unlock(kvm, itte->irq); + + return 0; } /* * Queries the KVM IO bus framework to get the ITS pointer from the given * doorbell address. * We then call vgic_its_trigger_msi() with the decoded data. + * According to the KVM_SIGNAL_MSI API description returns 1 on success. */ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi) { u64 address; struct kvm_io_device *kvm_io_dev; struct vgic_io_device *iodev; + int ret; if (!vgic_has_its(kvm)) return -ENODEV; @@ -490,10 +499,21 @@ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi) iodev = container_of(kvm_io_dev, struct vgic_io_device, dev); mutex_lock(&iodev->its->its_lock); - vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data); + ret = vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data); mutex_unlock(&iodev->its->its_lock); - return 0; + if (ret < 0) + return ret; + + /* + * KVM_SIGNAL_MSI demands a return value > 0 for success and 0 + * if the guest has blocked the MSI. So we map any LPI mapping + * related error to that. + */ + if (ret) + return 0; + else + return 1; } /* Requires the its_lock to be held. */ @@ -981,9 +1001,7 @@ static int vgic_its_cmd_handle_int(struct kvm *kvm, struct vgic_its *its, u32 msi_data = its_cmd_get_id(its_cmd); u64 msi_devid = its_cmd_get_deviceid(its_cmd); - vgic_its_trigger_msi(kvm, its, msi_devid, msi_data); - - return 0; + return vgic_its_trigger_msi(kvm, its, msi_devid, msi_data); } /* -- cgit v1.2.3-58-ga151 From 99e5e886a0a59df267ff6838f763b789847df982 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Mon, 1 Aug 2016 20:25:33 +0200 Subject: KVM: arm64: vgic-its: Handle errors from vgic_add_lpi During low memory conditions, we could be dereferencing a NULL pointer when vgic_add_lpi fails to allocate memory. Consider for example this call sequence: vgic_its_cmd_handle_mapi itte->irq = vgic_add_lpi(kvm, lpi_nr); update_lpi_config(kvm, itte->irq, NULL); ret = kvm_read_guest(kvm, propbase + irq->intid ^^^^ kaboom? Instead, return an error pointer from vgic_add_lpi and check the return value from its single caller. Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic/vgic-its.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 1bd8adbeae26..d06330abd5e8 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -51,7 +51,7 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid) irq = kzalloc(sizeof(struct vgic_irq), GFP_KERNEL); if (!irq) - return NULL; + return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&irq->lpi_list); INIT_LIST_HEAD(&irq->ap_list); @@ -522,7 +522,8 @@ static void its_free_itte(struct kvm *kvm, struct its_itte *itte) list_del(&itte->itte_list); /* This put matches the get in vgic_add_lpi. */ - vgic_put_irq(kvm, itte->irq); + if (itte->irq) + vgic_put_irq(kvm, itte->irq); kfree(itte); } @@ -713,10 +714,11 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, u32 device_id = its_cmd_get_deviceid(its_cmd); u32 event_id = its_cmd_get_id(its_cmd); u32 coll_id = its_cmd_get_collection(its_cmd); - struct its_itte *itte; + struct its_itte *itte, *new_itte = NULL; struct its_device *device; struct its_collection *collection, *new_coll = NULL; int lpi_nr; + struct vgic_irq *irq; device = find_its_device(its, device_id); if (!device) @@ -747,13 +749,24 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, return -ENOMEM; } + new_itte = itte; itte->event_id = event_id; list_add_tail(&itte->itte_list, &device->itt_head); } itte->collection = collection; itte->lpi = lpi_nr; - itte->irq = vgic_add_lpi(kvm, lpi_nr); + + irq = vgic_add_lpi(kvm, lpi_nr); + if (IS_ERR(irq)) { + if (new_coll) + vgic_its_free_collection(its, coll_id); + if (new_itte) + its_free_itte(kvm, new_itte); + return PTR_ERR(irq); + } + itte->irq = irq; + update_affinity_itte(kvm, itte); /* -- cgit v1.2.3-58-ga151 From 2cccbb368a2bf27d98cf36bb424fbbf5572c0fab Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Tue, 2 Aug 2016 22:05:42 +0200 Subject: KVM: arm64: vgic-its: Plug race in vgic_put_irq Right now the following sequence of events can happen: 1. Thread X calls vgic_put_irq 2. Thread Y calls vgic_add_lpi 3. Thread Y gets lpi_list_lock 4. Thread X drops the ref count to 0 and blocks on lpi_list_lock 5. Thread Y finds the irq via the lpi_list_lock, raises the ref count to 1, and release the lpi_list_lock. 6. Thread X proceeds and frees the irq. Avoid this by holding the spinlock around the kref_put. Reviewed-by: Andre Przywara Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic/vgic.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c index e7aeac719e09..e83b7fe4baae 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -117,17 +117,17 @@ static void vgic_irq_release(struct kref *ref) void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq) { - struct vgic_dist *dist; + struct vgic_dist *dist = &kvm->arch.vgic; if (irq->intid < VGIC_MIN_LPI) return; - if (!kref_put(&irq->refcount, vgic_irq_release)) + spin_lock(&dist->lpi_list_lock); + if (!kref_put(&irq->refcount, vgic_irq_release)) { + spin_unlock(&dist->lpi_list_lock); return; + }; - dist = &kvm->arch.vgic; - - spin_lock(&dist->lpi_list_lock); list_del(&irq->lpi_list); dist->lpi_list_count--; spin_unlock(&dist->lpi_list_lock); -- cgit v1.2.3-58-ga151 From d9ae449b3d14d7c55f69af329972f175d180e68d Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Wed, 3 Aug 2016 18:03:44 +0200 Subject: KVM: arm64: vgic-its: Make updates to propbaser/pendbaser atomic There are two problems with the current implementation of the MMIO handlers for the propbaser and pendbaser: First, the write to the value itself is not guaranteed to be an atomic 64-bit write so two concurrent writes to the structure field could be intermixed. Second, because we do a read-modify-update operation without any synchronization, if we have two 32-bit accesses to separate parts of the register, we can loose one of them. By using the atomic cmpxchg64 we should cover both issues above. Reviewed-by: Andre Przywara Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic/vgic-mmio-v3.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c index ff668e0dd586..90d81811fdda 100644 --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c @@ -306,16 +306,19 @@ static void vgic_mmio_write_propbase(struct kvm_vcpu *vcpu, { struct vgic_dist *dist = &vcpu->kvm->arch.vgic; struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; - u64 propbaser = dist->propbaser; + u64 old_propbaser, propbaser; /* Storing a value with LPIs already enabled is undefined */ if (vgic_cpu->lpis_enabled) return; - propbaser = update_64bit_reg(propbaser, addr & 4, len, val); - propbaser = vgic_sanitise_propbaser(propbaser); - - dist->propbaser = propbaser; + do { + old_propbaser = dist->propbaser; + propbaser = old_propbaser; + propbaser = update_64bit_reg(propbaser, addr & 4, len, val); + propbaser = vgic_sanitise_propbaser(propbaser); + } while (cmpxchg64(&dist->propbaser, old_propbaser, + propbaser) != old_propbaser); } static unsigned long vgic_mmio_read_pendbase(struct kvm_vcpu *vcpu, @@ -331,16 +334,19 @@ static void vgic_mmio_write_pendbase(struct kvm_vcpu *vcpu, unsigned long val) { struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; - u64 pendbaser = vgic_cpu->pendbaser; + u64 old_pendbaser, pendbaser; /* Storing a value with LPIs already enabled is undefined */ if (vgic_cpu->lpis_enabled) return; - pendbaser = update_64bit_reg(pendbaser, addr & 4, len, val); - pendbaser = vgic_sanitise_pendbaser(pendbaser); - - vgic_cpu->pendbaser = pendbaser; + do { + old_pendbaser = vgic_cpu->pendbaser; + pendbaser = old_pendbaser; + pendbaser = update_64bit_reg(pendbaser, addr & 4, len, val); + pendbaser = vgic_sanitise_pendbaser(pendbaser); + } while (cmpxchg64(&vgic_cpu->pendbaser, old_pendbaser, + pendbaser) != old_pendbaser); } /* -- cgit v1.2.3-58-ga151 From c7735769d5dd79afb07254532fabd9ccbd85b1fa Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Mon, 8 Aug 2016 16:45:43 +0100 Subject: KVM: arm64: ITS: move ITS registration into first VCPU run Currently we register an ITS device upon userland issuing the CTLR_INIT ioctl to mark initialization of the ITS as done. This deviates from the initialization sequence of the existing GIC devices and does not play well with the way QEMU handles things. To be more in line with what we are used to, register the ITS(es) just before the first VCPU is about to run, so in the map_resources() call. This involves iterating through the list of KVM devices and map each ITS that we find. Signed-off-by: Andre Przywara Reviewed-by: Eric Auger Tested-by: Eric Auger Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic/vgic-its.c | 43 +++++++++++++++++++++++++++++++++---------- virt/kvm/arm/vgic/vgic-v3.c | 8 ++++++++ virt/kvm/arm/vgic/vgic.h | 6 ++++++ 3 files changed, 47 insertions(+), 10 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index d06330abd5e8..1cf9f598c72a 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -1319,13 +1319,13 @@ void vgic_enable_lpis(struct kvm_vcpu *vcpu) its_sync_lpi_pending_table(vcpu); } -static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its) +static int vgic_register_its_iodev(struct kvm *kvm, struct vgic_its *its) { struct vgic_io_device *iodev = &its->iodev; int ret; - if (its->initialized) - return 0; + if (!its->initialized) + return -EBUSY; if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base)) return -ENXIO; @@ -1342,9 +1342,6 @@ static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its) KVM_VGIC_V3_ITS_SIZE, &iodev->dev); mutex_unlock(&kvm->slots_lock); - if (!ret) - its->initialized = true; - return ret; } @@ -1466,9 +1463,6 @@ static int vgic_its_set_attr(struct kvm_device *dev, if (type != KVM_VGIC_ITS_ADDR_TYPE) return -ENODEV; - if (its->initialized) - return -EBUSY; - if (copy_from_user(&addr, uaddr, sizeof(addr))) return -EFAULT; @@ -1484,7 +1478,9 @@ static int vgic_its_set_attr(struct kvm_device *dev, case KVM_DEV_ARM_VGIC_GRP_CTRL: switch (attr->attr) { case KVM_DEV_ARM_VGIC_CTRL_INIT: - return vgic_its_init_its(dev->kvm, its); + its->initialized = true; + + return 0; } break; } @@ -1529,3 +1525,30 @@ int kvm_vgic_register_its_device(void) return kvm_register_device_ops(&kvm_arm_vgic_its_ops, KVM_DEV_TYPE_ARM_VGIC_ITS); } + +/* + * Registers all ITSes with the kvm_io_bus framework. + * To follow the existing VGIC initialization sequence, this has to be + * done as late as possible, just before the first VCPU runs. + */ +int vgic_register_its_iodevs(struct kvm *kvm) +{ + struct kvm_device *dev; + int ret = 0; + + list_for_each_entry(dev, &kvm->devices, vm_node) { + if (dev->ops != &kvm_arm_vgic_its_ops) + continue; + + ret = vgic_register_its_iodev(kvm, dev->private); + if (ret) + return ret; + /* + * We don't need to care about tearing down previously + * registered ITSes, as the kvm_io_bus framework removes + * them for us if the VM gets destroyed. + */ + } + + return ret; +} diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c index 0506543df38a..9f0dae397d9c 100644 --- a/virt/kvm/arm/vgic/vgic-v3.c +++ b/virt/kvm/arm/vgic/vgic-v3.c @@ -289,6 +289,14 @@ int vgic_v3_map_resources(struct kvm *kvm) goto out; } + if (vgic_has_its(kvm)) { + ret = vgic_register_its_iodevs(kvm); + if (ret) { + kvm_err("Unable to register VGIC ITS MMIO regions\n"); + goto out; + } + } + dist->ready = true; out: diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h index 1d8e21d5c13f..6c4625c46368 100644 --- a/virt/kvm/arm/vgic/vgic.h +++ b/virt/kvm/arm/vgic/vgic.h @@ -84,6 +84,7 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu); int vgic_v3_probe(const struct gic_kvm_info *info); int vgic_v3_map_resources(struct kvm *kvm); int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address); +int vgic_register_its_iodevs(struct kvm *kvm); bool vgic_has_its(struct kvm *kvm); int kvm_vgic_register_its_device(void); void vgic_enable_lpis(struct kvm_vcpu *vcpu); @@ -140,6 +141,11 @@ static inline int vgic_register_redist_iodevs(struct kvm *kvm, return -ENODEV; } +static inline int vgic_register_its_iodevs(struct kvm *kvm) +{ + return -ENODEV; +} + static inline bool vgic_has_its(struct kvm *kvm) { return false; -- cgit v1.2.3-58-ga151 From 505a19eec49ab36b314a05bc062749ebdfb0aa90 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Tue, 9 Aug 2016 10:54:29 +0100 Subject: KVM: arm64: check for ITS device on MSI injection When userspace provides the doorbell address for an MSI to be injected into the guest, we find a KVM device which feels responsible. Lets check that this device is really an emulated ITS before we make real use of the container_of-ed pointer. [ Moved NULL-pointer check to caller of static function - Christoffer ] Signed-off-by: Andre Przywara Reviewed-by: Christoffer Dall Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic/vgic-its.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 1cf9f598c72a..9533080b47d3 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -471,6 +471,21 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, return 0; } +static struct vgic_io_device *vgic_get_its_iodev(struct kvm_io_device *dev) +{ + struct vgic_io_device *iodev; + + if (dev->ops != &kvm_io_gic_ops) + return NULL; + + iodev = container_of(dev, struct vgic_io_device, dev); + + if (iodev->iodev_type != IODEV_ITS) + return NULL; + + return iodev; +} + /* * Queries the KVM IO bus framework to get the ITS pointer from the given * doorbell address. @@ -494,9 +509,11 @@ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi) kvm_io_dev = kvm_io_bus_get_dev(kvm, KVM_MMIO_BUS, address); if (!kvm_io_dev) - return -ENODEV; + return -EINVAL; - iodev = container_of(kvm_io_dev, struct vgic_io_device, dev); + iodev = vgic_get_its_iodev(kvm_io_dev); + if (!iodev) + return -EINVAL; mutex_lock(&iodev->its->its_lock); ret = vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data); -- cgit v1.2.3-58-ga151 From 286054a7a8674b256da16564d96772b88896eb35 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Tue, 16 Aug 2016 17:51:06 +0100 Subject: KVM: arm64: ITS: avoid re-mapping LPIs When a guest wants to map a device-ID/event-ID combination that is already mapped, we may end up in a situation where an LPI is never "put", thus never being freed. Since the GICv3 spec says that mapping an already mapped LPI is UNPREDICTABLE, lets just bail out early in this situation to avoid any potential leaks. Signed-off-by: Andre Przywara Reviewed-by: Christoffer Dall Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic/vgic-its.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 9533080b47d3..4660a7d04eea 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -731,7 +731,7 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, u32 device_id = its_cmd_get_deviceid(its_cmd); u32 event_id = its_cmd_get_id(its_cmd); u32 coll_id = its_cmd_get_collection(its_cmd); - struct its_itte *itte, *new_itte = NULL; + struct its_itte *itte; struct its_device *device; struct its_collection *collection, *new_coll = NULL; int lpi_nr; @@ -749,6 +749,10 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, lpi_nr >= max_lpis_propbaser(kvm->arch.vgic.propbaser)) return E_ITS_MAPTI_PHYSICALID_OOR; + /* If there is an existing mapping, behavior is UNPREDICTABLE. */ + if (find_itte(its, device_id, event_id)) + return 0; + collection = find_collection(its, coll_id); if (!collection) { int ret = vgic_its_alloc_collection(its, &collection, coll_id); @@ -757,20 +761,16 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, new_coll = collection; } - itte = find_itte(its, device_id, event_id); + itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL); if (!itte) { - itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL); - if (!itte) { - if (new_coll) - vgic_its_free_collection(its, coll_id); - return -ENOMEM; - } - - new_itte = itte; - itte->event_id = event_id; - list_add_tail(&itte->itte_list, &device->itt_head); + if (new_coll) + vgic_its_free_collection(its, coll_id); + return -ENOMEM; } + itte->event_id = event_id; + list_add_tail(&itte->itte_list, &device->itt_head); + itte->collection = collection; itte->lpi = lpi_nr; @@ -778,8 +778,7 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, if (IS_ERR(irq)) { if (new_coll) vgic_its_free_collection(its, coll_id); - if (new_itte) - its_free_itte(kvm, new_itte); + its_free_itte(kvm, itte); return PTR_ERR(irq); } itte->irq = irq; -- cgit v1.2.3-58-ga151 From cabdc5c59ab46a1ec5ea98c5ac4022111fbfd63a Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 16 Aug 2016 15:03:02 +0100 Subject: KVM: arm/arm64: timer: Workaround misconfigured timer interrupt Similarily to f005bd7e3b84 ("clocksource/arm_arch_timer: Force per-CPU interrupt to be level-triggered"), make sure we can survive an interrupt that has been misconfigured as edge-triggered by forcing it to be level-triggered (active low is assumed, but the GIC doesn't really care whether this is high or low). Hopefully, the amount of shouting in the kernel log will convince the user to do something about their firmware. Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- virt/kvm/arm/arch_timer.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'virt') diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 4fde8c7dfcfe..77e6ccf14901 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -33,6 +33,7 @@ static struct timecounter *timecounter; static struct workqueue_struct *wqueue; static unsigned int host_vtimer_irq; +static u32 host_vtimer_irq_flags; void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) { @@ -365,7 +366,7 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) static void kvm_timer_init_interrupt(void *info) { - enable_percpu_irq(host_vtimer_irq, 0); + enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags); } int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value) @@ -432,6 +433,14 @@ int kvm_timer_hyp_init(void) } host_vtimer_irq = info->virtual_irq; + host_vtimer_irq_flags = irq_get_trigger_type(host_vtimer_irq); + if (host_vtimer_irq_flags != IRQF_TRIGGER_HIGH && + host_vtimer_irq_flags != IRQF_TRIGGER_LOW) { + kvm_err("Invalid trigger for IRQ%d, assuming level low\n", + host_vtimer_irq); + host_vtimer_irq_flags = IRQF_TRIGGER_LOW; + } + err = request_percpu_irq(host_vtimer_irq, kvm_arch_timer_handler, "kvm guest timer", kvm_get_running_vcpus()); if (err) { -- cgit v1.2.3-58-ga151